A Short Guide to Privilege in Expert Witness Reporting

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Privilege Generally: Common Law and Legislation

Client Legal Privilege allows parties in litigation to maintain the confidentiality of client-lawyer communications. A client can claim privilege over materials where those materials were produced for the ‘dominant purpose’ of providing legal advice to the client or assisting with litigation.

Sections 117, 118, and 119 of the Evidence Act 1995 (Cth) reinforce the ‘dominant purpose’ test for privilege and also extend the claim of privilege to materials that are confidential because of their intended advisory role in litigation, even where those materials have not been shown to a lawyer or client. An obvious example of such documentation is a draft expert report produced as a means for a party to determine their chances of success in litigation.

Dominant Purpose Test – What kind of Material?

When considering whether expert witness-related documents are privileged, determine whether the documents or materials in question were produced for the dominant purpose of providing legal advice or for litigation.

Regarding expert witness work, lawyers will find that related documents broadly fit two categories:

  1. Communications between experts and lawyers regarding the matter and the relevant report; and
  2. Materials that the expert has produced ‘unilaterally’, such as working notes, field notes, and the witness’s drafts of his or her report. (Roads Corporation v Love [2010] VSC 253 at [25])

Generally, clients may claim privilege over the first category of documents but not the second category. Notes and other ‘unilateral’ documentation are produced by an expert to assist him or herself in putting together the report but not for the main and prevailing purpose of communicating legal advice.

Has privilege been waived?

A client has the right to disclose privileged information and materials if they so choose (s 122 of the Evidence Act 1995 (Cth)). That is, the client may waive their privilege over expert witness related documents simply by expressly stating that they wish to do so.

The doctrine of privilege also takes the client to have waived their privilege where the client’s behaviour is inconsistent with the maintenance of confidentiality of documents. Submission of an expert witness report to the court for litigation will generally amount to an implied waiver of privilege over lawyer-expert communications, including the letter of instruction and documents attached to the brief. The reason for this is the court’s consideration of issues of fairness: if parties are permitted to disclose a significant portion of materials that assist their case but leave a portion of it confidential, parties may abuse this process to create an inaccurate perception of the disclosed material. Hence, the disclosure of an expert witness report will amount to a waiver of privilege over not only the report, but also materials which influenced the content of the report.

In principle, the rules around implied waivers of privilege are clear enough but in practice there is still much uncertainty about what actions amount to an implied waiver of privilege. There are a multitude of instances in which the unilateral work of the expert and communications affecting the content of reports are difficult to distinguish, leaving ambiguous the status of those supplementary materials after the report has been disclosed.  

Below are two common scenarios which bring up these issues and the current approaches of courts in resolving them.  

  • Draft Expert Reports

Courts are still not settled on whether draft expert reports should be protected by privilege. In many cases, opposing parties will request to see draft copies of expert reports from the opposing side for the purpose of proving that the expert had changed their mind under the undue influence of lawyers wishing to do more than simply settle the form of reports.

Some cases have preserved the protection of privilege over draft reports. Those cases concluded that privilege over draft reports performs the important function of allowing experts to change their opinions organically and honestly as their understanding of the matter develops. (Linter Group Ltd v Price Waterhouse (a firm) [1999] VSC 245 at [16]; Filipovski v Istland Maritime Ltd [2002] NSWLEC 177 at [22]). An obvious rebuttal to this argument, however, is the doctrine of implied privilege, as we have discussed above: where a draft report influences the content of the final report, it would be unfair to protect the confidentiality of the draft report when the final report has already been disclosed.  

In contrast, other cases have relied on consideration of the ‘dominant purpose’ of the production of the draft report in the first place. The courts in those matters have insisted on the importance of considering whether the draft report was produced as a part of the expert’s process of writing a final report or for presentation to lawyers for commentary. This is consistent with the emphasis at common law on the ‘dominant purpose test’: if the report was primarily produced to allow lawyers to consider their chances of success and settle the report, then the report drafts are protected by privilege (New Cap Reinsurance Corporation Ltd (In Liq) v Renaissance Insurance Ltd [2007] NSWSC 258; Shea v TruEnergy Pty Ltd (No 5) [2013] FCA 937).

  • Where the Expert Report refers to and cites privileged materials, which the expert uses to form their opinion

Generally, experts who refer to privileged material in forming their expert opinion do not cause the client to waive their privilege over those materials.

In Cole v Dyer [1999] SASC 272, the Defendant’s expert produced a report which particularised and relied upon statements the Defendant made to assessors hired by the Defendant’s lawyers. The Plaintiffs argued that they should be permitted to access the statements referred to in the expert report, whilst the Defendant claimed that those documents were privileged.

The Court in Cole v Dyer appealed mainly to a consideration of the ‘fairness’ to parties in requiring the Defendant to reveal otherwise privileged communications. It found that, since the expert had particularised the statement in his expert report, the Plaintiff’s solicitors could nonetheless adequately prepare for trial with the information included in the report. However, Chief Justice Doyle left open the possibility that the trial judge may require the Defendant to disclose the entirety of her statements. The Court considered that the trial judge may require this where, upon closer examination, the report has relied upon information from the statements that has not be particularised.

In the same case, the Court commented that issues with privilege might be avoided where lawyers provide a detailed and clear list in their Letter of Instruction of materials that experts should and should not use. Especially where confidential material is included as a source of information for the report, specificity about details in those materials relevant to the expert’s work will remove issues with partial disclosure.

Takeaways and Tips

Safeguard the client’s privilege over expert witness materials by:

  • Avoiding the disclosure of privileged material to the expert witness so that there is no way for the expert to disclose such material in their reporting.
  • Conducting a conference with the expert either in person or over Webex rather than producing written communication. This will be critical when assessing draft expert reports, which should be discussed over phone before finally handed to lawyers to settle, if at all. By avoiding written communication about reports where practical, lawyers can avoid making the communications discoverable by the opposing party without the claim of privilege. 
  • Providing a clear and transparent Letter of Instruction to the expert. If the lawyer has provided an expert witness with documents that are privileged but which the lawyer does not intend the expert to rely upon, it will assist the court to make this explicit in written communications with the expert.

If the above precautions are not taken, lawyers should proceed in their work with expert witnesses as if no documents are protected by privilege. The law on the client’s ability to claim privilege over many materials attached to expert witness reporting lacks consensus. It would therefore be prudent to assume that once the expert report has been submitted to court and the parties intend to rely on it in litigation, very little else will fall under the protection of Client Legal Privilege.

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